Filter assemblies, depth indicators, torque-limiting fittings, torque-indicating fittings, and systems incorporating the same

ABSTRACT

In some examples, a filter assembly may include a filter including a first gasket having a first channel adjacent to a first side of the filter and a second gasket having a second channel adjacent to a second side of the filter. The first gasket and the second gasket may include a beveled surface adjacent to the filter. The first channel and the second channel may include a diameter of from about 0.01 mm to about 0.5 mm. A finger tightening system may securely hold the filter without any leaks.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 63/047,469, filed Jul. 2, 2020, titled “FILTER ASSEMBLIES,DEPTH INDICATORS, TORQUE-LIMITING FITTINGS, AND SYSTEMS INCORPORATINGTHE SAME”, which is incorporated by reference in its entirety.

BACKGROUND

High-performance liquid chromatography (HPLC) may use operationalpressures in excess of 50 bar (5,000 kPa). HPLC systems may include anumber of components including filters that need to be fluid-tight,replaceable, and reconfigurable. These filters may include sinteredstainless steel or plastic disks that are retained in a housing. Thesefilters may additionally be encapsulated in a plastic or metal ringwhich aids in sealing the filters at high pressures, and are considered“open” filters because of the direct access of pressurized fluid to afilter face.

BRIEF DESCRIPTION OF DRAWINGS

Features of the present disclosure are illustrated by way of example andnot limited in the following figure(s), in which like numerals indicatelike elements, in which:

FIG. 1 is a perspective partial cross-section of a system including atorque-limiting fitting and a filter assembly, in accordance with anexample of the present disclosure;

FIG. 2 is a side cross-section of a system including a torque-limitingfitting, in accordance with an example of the present disclosure;

FIG. 3 is a side view of a system including a torque-limiting fitting,in accordance with an example of the present disclosure;

FIG. 4 is a distal perspective view of a driving collar seated within athumbpiece, in accordance with an example of the present disclosure;

FIGS. 5A-5D depict a two-color depth indicator, in accordance with anexample of the present disclosure;

FIGS. 6A and 6B are illustrate a system including a two-color depthindicator, in accordance with an example of the present disclosure;

FIG. 7A is a perspective cross-section of a filter assembly, inaccordance with an example of the present disclosure;

FIG. 7B is a perspective cross-section of a guard column assembly, inaccordance with an example of the present disclosure;

FIG. 8 is a perspective partial cross-section of a system including afilter assembly, in accordance with an example of the presentdisclosure;

FIG. 9 is a perspective partial cross-section of a system including atorque-indicating fitting, components of which may constitute a filterassembly, in use with a relatively short length filter cartridgeincluding a first type of gasket, in accordance with an example of thepresent disclosure;

FIG. 10 is a perspective view of the system of FIG. 9, in use with therelatively short length filter cartridge, in accordance with an exampleof the present disclosure;

FIG. 11 is a perspective partial cross-section of the system includingthe torque-indicating fitting of FIG. 9, in use with a relatively longlength filter cartridge including a second type of gasket, in accordancewith an example of the present disclosure;

FIG. 12 is a perspective view of the system of FIG. 11, in use with therelatively long length filter cartridge, in accordance with an exampleof the present disclosure;

FIG. 13 is a perspective view of a thumbpiece of the system of FIG. 9,including a driven coupler in the thumbpiece, in accordance with anexample of the present disclosure;

FIG. 14 is a perspective view of the filter cartridge of FIG. 9, withoutthe thread details on an external surface of a filter fitting, inaccordance with an example of the present disclosure;

FIG. 15 is a perspective view of the filter cartridge of FIG. 9, withthe thread details on the external surface of the filter fitting, inaccordance with an example of the present disclosure;

FIG. 16 is a perspective view of a driven coupler and atorque-indicating driving collar of the system of FIG. 9, in accordancewith an example of the present disclosure; and

FIG. 17 is a perspective view illustrating operation of the drivencoupler and the torque-indicating driving collar of FIG. 16, inaccordance with an example of the present disclosure.

DETAILED DESCRIPTION

For simplicity and illustrative purposes, the present disclosure isdescribed by referring mainly to examples. In the following description,numerous specific details are set forth in order to provide a thoroughunderstanding of the present disclosure. It will be readily apparenthowever, that the present disclosure may be practiced without limitationto these specific details. In other instances, some methods andstructures have not been described in detail so as not to unnecessarilyobscure the present disclosure.

Throughout the present disclosure, the terms “a” and “an” are intendedto denote at least one of a particular element. As used herein, the term“includes” means includes but not limited to, and the term “including”means including but not limited to. The term “based on” means based atleast in part on.

Unless specifically stated or obvious from context, as used herein, theterm “about” is understood as within a range of normal tolerance in theart, for example within 2 standard deviations of the mean. “About” canbe understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%,0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear fromcontext, all numerical values provided herein are modified by the termabout.

Unless specifically stated or obvious from context, the term “or,” asused herein, is understood to be inclusive.

Ranges provided herein are understood to be shorthand for all of thevalues within the range. For example, a range of 1 to 50 is understoodto include any number, combination of numbers, or sub-range from thegroup consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34,35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 (aswell as fractions thereof unless the context clearly dictatesotherwise).

Examples described herein relate to systems capable of fluid-tightcouplings without the need for tools such as wrenches, screwdrivers, andthe like.

According to examples disclosed herein, a filter assembly may include afilter, a first gasket adjacent to a first side of the filter, a secondgasket adjacent to a second side of the filter, a female housing, and amale housing. The male housing may be sized to fit concentrically withinthe female housing. Each of the male housing and female housing mayinclude a bore, and a stop shoulder surrounding the bore. Each of thefirst gasket and second gasket may include a complementary geometry toform a seal against a respective stop shoulder.

For the filter assembly described above, the bores may define a centralaxis. In this regard, the stop shoulders may be perpendicular to thecentral axis. The filter, the first gasket, the second gasket, thefemale housing, and the male housing may be radially symmetric about thecentral axis.

For the filter assembly described above, the first gasket and the secondgasket each may include a central axial bore.

For the filter assembly described above, the first gasket and the secondgasket may include a beveled surface adjacent to the filter. The beveledsurface may include an angle relative to a central axis of from about 70degrees to about 89 degrees.

For the filter assembly described above, fluid flow pressure about thefilter may produce increased sealing pressure between the complementarygeometry of the first and second gaskets and respective stop shoulder ofthe female and male housings relative to a pre-flow state.

For the filter assembly described above, the filter assembly may befluid-tight at fluid-flow pressures of 1,300 bar (130,000 kPa) withoutrequiring a pre-flow sealing pressure above 13 pounds-force (57.8 N).

For the filter assembly described above, the male housing and the femalehousing may be press-fit together or are threaded together.

For the filter assembly described above, the filter may include a firstfilter, a second filter, and a media between the first filter and thesecond filter.

According to examples disclosed herein, a filter assembly may include, afilter, a first gasket having a first channel adjacent to a first sideof the filter, and a second gasket having a second channel adjacent to asecond side of the filter. The first gasket and the second gasket mayinclude a beveled surface adjacent to the filter. The first channel andthe second channel may include a diameter of from about 0.01 mm to about0.5 mm.

According to examples disclosed herein, a guard column assembly mayinclude a first filter, a second filter, a media positioned between thefirst filter and the second filter, a first gasket having a firstchannel adjacent to the first filter, and a second gasket having asecond channel adjacent to the second filter. The first gasket and thesecond gasket may include a beveled surface adjacent to the first filterand the second filter, respectively. The first channel and the secondchannel may include a diameter of from about 0.01 mm to about 0.5 mm.

According to examples disclosed herein, a system may include a femalehousing including internal helical threads, a male housing includingexternal helical threads and defining an axial bore adapted andconfigured to receive a filter or a guard column assembly, and atwo-color depth indicator positioned external to the male housing or thefemale housing. The two-color depth indicator may include a distalcolor, and a proximal color. The distal color and the proximal color maybe positioned such that, when the female housing or the male housing aretightened over the counterpart male housing or the female housing, ifthe filter assembly is correctly inserted and the two-color depthindicator is positioned external to the male housing, then the femalehousing may cover the proximal color such that only the distal color isvisible and if the filter assembly is correctly inserted and thetwo-color depth indicator is positioned external to female housing, thena cover may hide the proximal color such that only the distal color isvisible. If the filter assembly is incorrectly inserted or is defective,both the proximal color and the distal color may be visible. If nofilter assembly is inserted, the female housing or the cover may hideboth the proximal color and the distal color such that neither theproximal color nor the distal color are visible.

For the system described above, the two-color depth indicator may beformed through at least one process including printing, painting,electroplating, brush electroplating, or anodizing.

For the system described above, the two-color depth indicator may be aring placed over the external helical threads of the male housing. Thering may be threaded over the external helical threads of the malehousing.

For the system described above, the two-color depth indicator mayinclude an adhesive tape, a sticker, and a rubber band.

For the system described above, the female housing may further include adistal, unthreaded portion adjacent to the internal helical threads. Thedistal, unthreaded portion may include an axial length equal to orexceeding an axial length of the two-color depth indicator.

For the system described above, the distal color may be green, and theproximal color may be red.

According to examples disclosed herein, a torque-limiting fitting mayinclude a driven coupler including a sealing region, and at least onedriven tooth including, in a sealing direction of the driven coupler, asloped rotationally trailing surface. A driving collar may include atleast one driving tooth positioned to engage with the at least onedriven tooth as the driving collar is rotated.

For the torque-limiting fitting described above, the torque-limitingfitting may further include a resilient member adjacent to the drivingcollar.

For the torque-limiting fitting described above, a thumbpiece may coverat least the driving collar and the resilient member. The thumbpiece mayinclude a recess accommodating the driving collar and the resilientmember, and at least one advancement-limiting feature adapted andconfigured to limit axial movement of the thumbpiece.

For the torque-limiting fitting described above, the sealing region mayinclude helical threads. The sealing region may be located on a distalend of the driven coupler.

For the torque-limiting fitting described above, the at least one driventooth may be located on a proximal end or on a radially outer surface ofthe driven coupler.

For the torque-limiting fitting described above, the at least onedriving tooth may include an asymmetric profile rotationally opposite tothe at least one driven tooth.

For the torque-limiting fitting described above, the driving collar mayfurther include at least one axial collar-alignment feature. The atleast one axial collar-alignment feature may be located radially outerfrom or inner to the at least one driving tooth. The at least oneadvancement-limiting feature may include a stop shoulder.

For the torque-limiting fitting described above, the thumbpiece and thedriven coupler may further include complementary features to hold thethumbpiece and the driven coupler together with the driving collar andthe resilient member held between. The complementary feature may includea first radial undercut, and a second radial undercut and/or at leastone boss.

For the torque-limiting fitting described above, the driven coupler andthe driving collar may be formed from metal.

For the torque-limiting fitting described above, the resilient membermay include a wave spring.

For the torque-limiting fitting described above, the thumbpiece mayinclude a knurled outer surface. The thumbpiece may further include atleast one axial thumbpiece-alignment feature complementary to at leastone axial collar-alignment feature.

According to examples disclosed herein, a filter assembly may include adriven coupler engageable with a filter fitting of a filter cartridge.The driven coupler may include a bore to receive the filter fitting, anda stop shoulder surrounding the bore to limit movement of the drivencoupler relative to the filter fitting.

For the filter assembly described above, the driven coupler may includean internal thread for threaded engagement with an external thread ofthe filter fitting.

For the filter assembly described above, the stop shoulder of filterfitting may be perpendicular to a central axis of the filter assembly.

For the filter assembly described above, the driven coupler, the filterfitting, and the filter cartridge may be radially symmetric about acentral axis of the filter assembly.

For the filter assembly described above, the filter assembly may furtherinclude a thumbpiece engageable with the driven coupler to rotate thedriven coupler.

According to examples disclosed herein, a filter cartridge may include afirst filter fitting on one side of a filter, a second filter fitting ona second opposite side of the filter, a first gasket disposed in thefirst filter fitting, and a second gasket disposed in the second filterfitting.

For the filter cartridge described above, the first filter fitting andthe second filter fitting may include external threads.

For the filter cartridge described above, the first gasket and secondgasket may include a complementary geometry to respectively form a sealagainst a stop shoulder of the first filter fitting and a stop shoulderof the second filter fitting.

For the filter cartridge described above, the stop shoulder of the firstfilter fitting and the stop shoulder of the second filter fitting may beperpendicular to a central axis of the filter cartridge.

For the filter cartridge described above, the first filter fitting, thesecond filter fitting, the first gasket, and the second gasket may beradially symmetric about a central axis of the filter cartridge.

For the filter cartridge described above, the first gasket and thesecond gasket each may include a central axial bore.

For the filter cartridge described above, the first gasket and thesecond gasket may include a beveled surface adjacent to the filter. Thebeveled surface may include an angle relative to a central axis of thefilter cartridge from about 70 degrees to about 89 degrees.

According to examples disclosed herein, a torque-indicating fitting mayinclude a driven coupler including at least one driven tooth, and atorque-indicating driving collar including at least one driving toothpositioned to engage with the at least one driven tooth as thetorque-indicating driving collar is rotated. The torque-indicatingdriving collar may further include at least one torque-indicating toothpositioned adjacent to the at least one driving tooth to engage with theat least one driven tooth as the torque-indicating driving collar isrotated.

The torque-indicating fitting may further include a resilient memberadjacent to the torque-indicating driving collar, and a thumbpiececovering at least the torque-indicating driving collar and the resilientmember. The thumbpiece may include a recess accommodating thetorque-indicating driving collar and the resilient member, and at leastone advancement-limiting feature adapted and configured to limit axialmovement of the thumbpiece.

For the torque-indicating fitting described above, the at least onedriven tooth may be located on a proximal end or on a radially outersurface of the driven coupler.

For the torque-indicating fitting described above, the torque-indicatingdriving collar may further include at least one axial collar-alignmentfeature. The at least one axial collar-alignment feature may be locatedradially outer from or inner to the at least one driving tooth.

For the torque-indicating fitting described above, the at least oneadvancement-limiting feature may include a stop shoulder.

For the torque-indicating fitting described above, the thumbpiece andthe driven coupler may further include complementary features to holdthe thumbpiece and the driven coupler together with thetorque-indicating driving collar and the resilient member held between.The complementary features may include a thumbpiece protrusion and adriven coupler protrusion.

For the torque-indicating fitting described above, the driven couplerand the torque-indicating driving collar may be formed from metal.

For the torque-indicating fitting described above, the resilient membermay be a wave spring.

For the torque-indicating fitting described above, the thumbpiece mayinclude a knurled outer surface.

For the torque-indicating fitting described above, the thumbpiece mayfurther include at least one axial thumbpiece-alignment featurecomplementary to at least one axial collar-alignment feature.

FIG. 1 provides a partial cross-section of a system 100 for coupling ofa filter assembly 102 or a guard column 700 b (FIG. 7B), for example, toa liquid chromatograph system. The system 100 may include fittings 104 aand 104 b, a driven coupler 108, a thumbpiece 110, a driving collar 120,a resilient member 126, such as a spring, and a cover 134. In anexample, the driven coupler 108 may be rotatably positioned around thefitting 104 a. The driving collar 120 may be positioned on top of thedriven coupler 108, such that it may engage or disengage from the drivencoupler 108 via the resilient member 126. The resilient member 126 maybe positioned on top of or adjacent to the driving collar 120, such thatwhen a torque applied by turning the thumbpiece 110 reaches apredetermined amount, the resilient member 126 allows the driving collar120 to disengage from the driven coupler 108. Thus, in this example, thethumbpiece 110 is positioned and connected to the resilient member 126and the driving collar 120. A user, by rotating the thumbpiece 110, maycause the driving collar 120 to engage and rotate the driven coupler 108to removably connect the driven coupler 108 to the exterior surface ofthe fitting 104, thereby connecting the fitting 104a to the fitting 104b. Filter assembly 102 may be held between and fluidically coupled tofittings 104 a and 104 b, which may be coupled to other components of anLC system, e.g., by swaging and other techniques. Filter assembly 102may be held between fittings 104 a and 104 b by a connection between thedriven coupler 108, which may be in a form of a female housing, and thefitting 104b, which may be in a form of a male housing. In an example, aportion of the inner surface of the driven coupler 108 may include asealing region, for example a set of helical threads 106, thatcorrespond to a portion of the exterior surface of the fitting 104 bthat includes a second sealing region, for example, a set of secondhelical threads 106. By connecting the helical threads 106 of the drivencoupler 108 and the fitting 104 b, the fittings 104 a and 104 b maysecurely hold the filter assembly 102.

Torque-Limiting Fitting

Referring to FIG. 2, in an example, the system 100 may provide atorque-limiting fitting. The torque applied to the driven coupler 108when a user rotates the thumbpiece 110 maybe controlled, for example, toprevent damage to components and facilitate later removal. In anexample, the force applied to the driven coupler 108 may be from about 1Pounds-force (lbf) or less to about 32 lbf, for example, the force maybe from about 2 lbf to about 24 lbf, from about 3 lbf to about 13 lbf,such as about 5 lbf.

As best seen in FIG. 3, the driven coupler 108 may include one or moreasymmetric driven teeth 112. The asymmetric driven teeth 112 may includea rotationally leading surface 114 and a rotationally trailing surface116. When the driven coupler 108 is turned in a sealing direction (e.g.,counterclockwise in the example depicted in FIG. 3), the rotationallytrailing surface 116 has a lower slope than the rotationally leadingsurface 114. Examples of slopes for trailing surface 116 (relative to aradial plane) may include less than about 90°, such as about 45°, fromabout 45° to about 15°, from about 30° to about 15°, about 22.5°, andthe like. Examples of slopes for surface 114 (relative to a radialplane) may include about 90° or less, such as from about 90° to about75°, from about 85° to about 75°, and the like.

The driven coupler 108 may be driven by a driving collar 120 having oneor more driving teeth 122 positioned to engage with the one or moreasymmetric driven teeth 112 as the driving collar 120 is rotated via theforce applied by the user to the thumbpiece 110 (shown in FIGS. 1 and2). The driving teeth 122 may, but need not have an opposite, asymmetricprofile relative to asymmetric driven teeth 112. In some examples, theslopes are identical, which may facilitate frictional engagement betweendriving teeth 122 and asymmetric driven teeth 112.

Referring to FIGS. 3 and 4, the driving collar 120 may include one ormore axial collar-alignment features 124. Although axialcollar-alignment features 124 depicted in FIGS. 3 and 4 are radiallyouter bosses or ridges, axial collar-alignment features 124 could beradially inner, grooves, and the like.

The resilient member 126 adjacent to the driving collar 120 may pressthe driving collar 120 against the driven coupler 108. Driving collar120 may slide axially within axial thumbpiece-alignment features 128complementary to the one or more axial collar-alignment features 124.The properties of the various components may be configured to allow thedriving teeth 122 to frictionally engage with and drive asymmetricdriven teeth 112 until a defined amount of torque is applied (e.g., adriven coupler 108 forms a threaded seal with the helical threads 106located on the surface of the fitting 104 b and resists furtherrotation). When the torque exceeds the configured threshold, the drivingteeth 122 will slip and overcome the axial force applied by theresilient member 126. Thus, the driving collar 120 will slide proximallywithin the thumbpiece 110. The higher-sloped surface 114 will be moreresistant to slipping and ensure easy removal even if the driven coupler108 was tightened to the point of teeth slippage.

As best seen in FIGS. 1 and 2, the thumbpiece 110 may cover at least thedriving collar 120 and resilient member 126, which may rest in aproximal recess in order to allow deformation of resilient member 126and axial movement of driving collar 120. The thumbpiece 110 may beretained through one or more features such a radial undercuts 130 a, 130b on driven coupler 108 and thumbpiece 110, respectively, that allow thethumbpiece 110 to rotate over the driven coupler 108 when the teeth 112,122 slip during tightening.

Still referring to FIGS. 1 and 2, the thumbpiece 110 and/or the drivencoupler 108 may include one or more advancement-limiting features 132a-132 d, such as stop shoulders adapted and configured to limit orprevent axial movement of the thumbpiece 110. Such advancement-limitingfeatures 132 a-132 d prevent a user from overcoming the torque-limitingfeatures by pressing the thumbpiece 110 distally during rotation, whichwould further load the resilient member 126 and/or the driving collar120 and reduce or prevent the ability of the driving teeth 122 to slipand the driving collar 120 to slide proximally.

The thumbpiece 110 may, but need not, be knurled, roughened, or includeone or more features to aid in finger-tightening.

Visual Depth Indicator

Referring now to FIGS. 5A-5D, some examples of the system 100 mayinclude a two-color depth indicator 500. The two-color depth indicator500 may include two color regions 502 and 504 of different colors. Theregions may be axially arranged such that the color region 502 isproximal and the color region 504 is distal relative to a radially outercomponent 506 (e.g., covering component).

Two-color depth indicator 500 may be positioned on an exterior surfaceso that the user may visualize the two-color depth indicator 500 and useit to assess whether a system is properly assembled. For example,referring to FIG. 2, two-color depth indicator 500 could be positionedon an exterior surface of driven coupler 108 and an exterior surface offitting 104 b (if cover 134 may slide distally so that the user may viewfitting 104 b), and the like. In another example, the driven coupler 108may include two color regions 502 and 504. In this example, the colorregion 502 may be the exterior of the driven coupler 108 thatcorresponds to the threaded section in the interior surface of thedriven coupler 108. Additionally, the color region 504 may correspond tothe remaining exterior portion of the driven coupler 108. As a userscrews the driven coupler 108 to the exterior surface of the fitting 104b, the cover 134 starts to cover exterior surface of the driven coupler108 having the color region 502. When the driven coupler 108 is fullyconnected to the fitting 104 b, the cover 134 may completely cover thecolor region 502; therefore, only the color region 504 may be visible tothe user. The visibility of the single color region 504 is an indicationthat the driven coupler 108 is completely secured to the fitting 104 b.

Two-color depth indicator 500 may be positioned along an exteriorsurface that is partially covered by another component 506 (e.g., drivencoupler 108 in the case of fitting 104 b, cover 134 in the case ofdriven coupler 108, and the like). The radially outer component 506 isdepicted as partially transparent so that two-color depth indicator 500may be visualized underneath. In some examples, the radially outercomponent 506 may be optically opaque.

Referring now to FIG. 5B, if a component is incorrectly assembled or isdefective, both the proximal color region 502 and the distal colorregion 504 may be seen.

Referring now to FIG. 5C, if a component is correctly assembled, onlythe distal color region 504 may be seen.

Referring now to FIG. 5D, if a component (e.g., filter assembly 102) ismissing, neither the proximal color region 502 nor the distal colorregion 504 may be seen.

FIGS. 6A and 6B illustrate a system including a two-color depthindicator 500. The proximal color region 502 (red) and the distal colorregion 504 (green) may both be seen in FIG. 6A, indicating that theradially outer component 506 (e.g., thumbpiece) may need to be furthertightened or that the filter assembly 102 is defective or improperlyinstalled. In FIG. 6B, only the distal color 504 (green) may be seen,indicating that the radially outer component 506 (e.g., thumbpiece) istightened properly.

The two-color depth indicator 500 may be annular or a strip. Thetwo-color depth indicator 500 may be formed through various processessuch as printing, painting, electroplating, brush electroplating,anodizing, and the like. The two-color depth indicator 500 may be anadhesive tape, a sticker, a rubber band, and the like. In one example,the two-color depth indicator 500 may be one or two colored rings thatare installed (e.g., over external helical threads by threading,adhesive, or the like).

Filter Assembly

Referring now to FIG. 7A, another example provides a filter assembly 700a. The filter assembly 700 a advantageously remains fluid-tight whensubject to elevated fluid pressure, e.g., greater than 50 bar (5,000kPa), 350 bar (35,000 kPa), 1,000 bar (100,000 kPa), 1,300 bar (130,000kPa), and the like without requiring significant pre-flow tightening ofthe system 100, e.g., over 7 pounds-force (about 58 N).

Filter 702 is held within the filter assembly 700 a and may be of thetype used in HPLC. For example, the filter 702 may be a sintered frit,such as 300 series sintered steel.

Gaskets 704 a, 704 b may sit proximally and distally to the filter 702.The gaskets 704 a, 704 b define a first channel 706 a and a secondchannel 706 b for fluid inflow and outflow. The first and secondchannels 706 a and 706 b may be centered (e.g., axially) and/orsurrounded by an exterior gasket face 708 a, 708 b to form a seal withfittings 104 a and 104 b as best seen in FIG. 8. In an example, each ofthe first and second channels 706 a and 706 b may include a diameter offrom about 0.01 mm or less to about 0.9 mm, for example from about 0.1mm to about 0.5 mm, such as a diameter of about 0.3 mm.

Filter 702 and gaskets 704 a, 704 b are held between a female housing712 and a male housing 710. Female housing 712 and male housing 710 maybe held together through a variety of techniques including aninterference fit, a press fit, a friction fit, a shrink fit, threading,welding, ultrasonic welding, adhesives, fasteners, and the like. In someexamples, the female housing 712 and male housing 710 are held togetherthrough one or more features such as a radial undercut 714 andcorresponding boss or ridge 716. In some examples, the female housing712 and male housing 710 are assembled using a press and sold as a unitto end users. In an example, the female housing 712 may be made ofpolymers, a metal, or a combination of metals. For example, the femalehousing may be made of steel such as 17-4 steel. Similarly, the malehousing 710 may be made of a metal or a combination of metals. Forexample, the male housing may be made of steel, such as 300 seriessteel.

Gaskets 704 a, 704 b may include one or more geometric features adaptedand configured to provide a fluid-tight seal under pressure. Forexample, the gaskets 704 a, 704 b may include a stop shoulder 720 a, 720b complementary to a stop shoulder 722 a, 722 b surrounding a bore(e.g., an axial bore) on gaskets 704 a, 704 b.

Gaskets 704 a, 704 b may also include a beveled surface 718 a, 718 badjacent to the filter 702. The beveled surface 718 a, 718 b may have aconical profile centered around first and second channels 706 a, 706 b.The bevel may be (with respect to a radial plane) from about 5° to about20 and the like. In other examples, the angle relative to a central axismay be from about 70 degrees (e.g., 20° with respect to a radial plane)to about 89 degrees (e.g., 1° with respect to a radial plane).

During operation, fluid pressure on the beveled surfaces 718 a, 718 bmay primarily generate axially sealing pressure against stop shoulders722 a, 722 b and/or radial sealing pressure against male housing 710.Thus, the higher the fluid pressure, the higher sealing pressure andmore fluid-tight the filter assembly 700 a. Accordingly, fingertightening force of from about 3 lbf to about 13 lbf, such as about 5lbf to about 8 lbf on the system 100 is sufficient to completely sealthe filter assembly 700 a without the need to use external forces tofurther tighten the system 100.

In another example, a guard column 700 b may advantageously remainfluid-tight when subject to elevated fluid pressure, e.g., greater than50 bar (5,000 kPa), 350 bar (35,000 kPa), 1,000 bar (100,000 kPa), 1,300bar (130,000 kPa), and the like without requiring significant pre-flowtightening, e.g., over 13 pounds-force (about 57.8 N).

In this example, the guard column 700 b may include a first filter 702a, a second filter 702 b and a media 703 positioned between the firstfilter 702 a and the second filter 702 b. The first filter 702 a, thesecond filter 702 b and the media 703 may be of any type used in HPLC,including, but not limited to ultra high-performance liquidchromatography (UHPLC). For example, the filters 702 a and/or 702 b maybe a sintered frit made of metals, polymers, or a combination thereof.In this example, the media 703 may be made of particles, such as,metals, metal oxides, polymers, carbon (e.g., spherical shaped activatedcarbon, or carbon on silica material), silica-based particles or genericversions thereof, activated charcoal, stationary phase, etc. In otherexamples, the media 703 may include other types of material that areoptimized for the solvent cleanup, and other such uses. The media and/orparticles disclosed herein may be used for any of the filters disclosedherein, and/or other types of columns, online solid phase extraction(SPE), etc. One or more of filters 702 a, 702 b, and/or the media 703may also be made of monolith.

Gaskets 704 a and 704 b may sit proximally and distally to the filters702 a and 702 b. The gaskets 704 a and 704 b define a first channel 706a and a second channel 706 b for fluid inflow and outflow. Each of thefirst and second channels 706 a and 706 b may be centered (e.g.,axially) and/or surrounded by an exterior gasket face 708 a and 708 b toform a seal with fittings 104 a and 104 b. In an example, each of thefirst and second channels 706 a and 706 b may include a diameter of fromabout 0.01 mm or less to about 0.9 mm, for example from about 0.1 mm toabout 0.5 mm, such as a diameter of about 0.3 mm.

Each of the filters 702 a, 702 b, the media 703, and the gaskets 704 a,704 b are held between a female housing 712 and a male housing 710.Female housing 712 and male housing 710 may be held together through avariety of techniques including an interference fit, a press fit, afriction fit, a shrink fit, threading, welding, ultrasonic welding,adhesives, fasteners, and the like. In some examples, the female housing712 and male housing 710 are held together through one or more featuressuch as a radial undercut 714 and corresponding boss or ridge 716. Insome examples, the female housing 712 and male housing 710 may beassembled using a press and sold as a unit to end users.

Gaskets 704 a and 704 b may include one or more geometric featuresadapted and configured to provide a fluid-tight seal under pressure. Forexample, the gaskets 704 a and 704 b may include a stop shoulder 720 aand 720 b complementary to a stop shoulder 722 a and 722 b surrounding abore (e.g., an axial bore) on gaskets 704 a and 704 b.

Gaskets 704 a and 704 b may also include beveled surfaces 718 a and 718b adjacent to the filters 702 a and 702 b. The beveled surfaces 718 aand 718 bmay have a conical profile centered around the first and secondchannels 706 a and 706 b. The bevel may be (with respect to a radialplane) from about 5° to about 20° and the like.

During operation, fluid pressure on the beveled surfaces 718 a and 718 bprimarily generated axially sealing pressure against stop shoulders 722a and 722 b and/or generates radial sealing pressure against malehousing 710. Thus, the higher the fluid pressure, the higher sealingpressure and more fluid-tight the guard column 700 b. Accordingly,finger tightening force of from about 3 lbf to about 13 lbf, such asabout 5 lbf to about 8 lbf on the system 100 is sufficient to completelyseal the filter assembly 700 a without the need to use external forcesto further tighten the system 100.

EXAMPLES

An Open Face type filter element (prior art) and closed face inlinefilter design of the current invention (FIG. 7B) were tested for thepreload needed to seal at given applied pressure. The pressure wasgenerated by an Agilent 1290 Infinity II LC pump using isopropylalcohol. A schematic of the test fixture is shown below (FIG. 9)

Procedure: The filter was inserted into the fixture, resting on the sealblock. The compression ring was tightened to a reading of 5 lb. preload,pressing the filter between the seal block and the nut body. The testwould start and if the set pressure (bar) was not achieved, thecompression ring would further tighten, increasing the load. Once thepressure graph showed the desired pressure has been reached and once theflow graph showed the leak rate was no longer decreasing, thecompression ring was no longer tightened, and the system was held at theset pressure. Each run was −90 seconds in length. At the end of thetest, the pressure returned to ambient. The current load reading (lbs.)and the resultant leak rate (uL/min) were recorded. The open and closedface configurations were tested with three filters each, at 200, 400,and 600 bar.

Open Face Filter Leak Pressure Preload Rate Filter (bar) (lbs.) (uL/min)OF1 200 218 3.87 400 229 7.587 600 333 11.46 OF2 200 204 3.73 400 2307.73 600 391 65 OF3 200 137 6.4 400 157 7.2 600 214 2.13

Closed Face Filter Leak Pressure Preload Rate Filter (bar) (lbs.)(uL/min) CF1 200 5 <0.1 400 5 <0.1 600 7 <0.1 CF2 200 5 <0.1 400 5 <0.1600 5 0.13 CF3 200 5 <0.1 400 5 <0.1 600 5 <0.1

All open face filters required a high preload to form a seal andresulted in comparably high leak rates. The closed face filtercartridges required a minimal preload (finger-tight) to achieve aleak-free seal.

Torque-Indicating Fitting

FIG. 9 is a perspective partial cross-section of a system 900 includinga torque-indicating fitting 902, components of which may constitute afilter assembly 904, in use with a relatively short length filtercartridge 906 including a first type of gasket 908, in accordance withan example of the present disclosure. FIG. 10 is a perspective view ofthe system 900, in use with the relatively short length filter cartridge906, in accordance with an example of the present disclosure. FIG. 11 isa perspective partial cross-section of a system 1100 including thetorque-indicating fitting 902, in use with a relatively long lengthfilter cartridge 1102 including a second type of gasket 1104, inaccordance with an example of the present disclosure. FIG. 12 is aperspective view of the system 1100, in use with the relatively longlength filter cartridge 1102, in accordance with an example of thepresent disclosure.

Referring to FIGS. 9 and 10, the filter assembly 904, which may includeany two or more components of the torque-indicating fitting 902, mayinclude a driven coupler 910 engageable with a filter fitting 912 of afilter cartridge 906. The filter assembly 904 may also include atorque-indicating driving collar 914 as disclosed herein. The drivencoupler 910 may include a bore 916 to receive the filter fitting 912,and a stop shoulder 918 surrounding the bore 916 to limit movement ofthe driven coupler 910 relative to the filter fitting 912.

The stop shoulder 918 of the filter fitting 912 may be perpendicular toa central axis 920 of the filter assembly 904. The driven coupler 910,the filter fitting 912, and the filter cartridge 906 may be radiallysymmetric about the central axis 920 of the filter assembly 904.

The driven coupler 910 may include an internal thread 922 for threadedengagement with an external thread 924 of the filter fitting 912 (e.g.,see also FIG. 15).

For the example of FIG. 9, the gasket 908 may include a complementarygeometry 926 that reduces in diameter towards a central direction of thefilter cartridge 906. For example, a diameter of the gasket 908 reducesfrom a larger diameter adjacent to a fitting 928, to a smaller diameteradjacent to frit 954. In this manner, the gasket 908 may form a sealagainst a corresponding filter fitting.

The torque-indicating fitting 902 and the relatively short length filtercartridge 906 may be fluidically coupled to fittings 928 and 930, whichmay be further coupled to other components of a liquid chromatography(LC) system, for example, by swaging and other techniques.

The filter assembly 904 may further include a thumbpiece 932 engageablewith the driven coupler 910 to rotate the driven coupler 910. FIG. 13 isa perspective view of the thumbpiece 932 of the system 900 (and 1100),including the driven coupler 910 in the thumbpiece 932, in accordancewith an example of the present disclosure.

As shown in FIG. 9, the torque-indicating fitting 902 may furtherinclude a resilient member 944 adjacent to the torque-indicating drivingcollar 914. The thumbpiece 932 may cover at least the torque-indicatingdriving collar 914 and the resilient member 944. The thumbpiece 932 mayinclude a recess 946 accommodating the torque-indicating driving collar914 and the resilient member 944, and at least one advancement-limitingfeature 948 adapted and configured to limit axial movement of thethumbpiece 932. The at least one advancement-limiting feature 948 mayinclude a stop shoulder.

The thumbpiece 932 and the driven coupler 910 may further includecomplementary features to hold the thumbpiece 932 and the driven coupler910 together with the torque-indicating driving collar 914 and theresilient member 944 held between. The complementary features mayinclude a thumbpiece protrusion 950 and a driven coupler protrusion 952.

Referring to FIGS. 9 and 16, the thumbpiece 932 may further include atleast one axial thumbpiece-alignment feature (similar tothumbpiece-alignment features 128 of FIG. 4) complementary to at leastone axial collar-alignment feature 1616 of the torque-indicating drivingcollar 914 (e.g., see FIG. 16). In the example of FIG. 16, the axialcollar-alignment feature 1616 is shown as radially outer bosses orridges, but may instead include radially inner grooves and the like.

In some examples, the thumbpiece 932 may include a knurled outersurface. The knurled outer surface may facilitate manual (e.g., by hand)rotation of the thumbpiece 932 to attach the torque-indicating fitting902 onto the filter cartridge 906 (or 1102), or to detach thetorque-indicating fitting 902 from the filter cartridge 906 (or 1102).

The filter assembly 904 advantageously remains fluid-tight when subjectto elevated fluid pressure, e.g., greater than 50 bar (5,000 kPa), 350bar (35,000 kPa), 1,000 bar (100,000 kPa), 1,300 bar (130,000 kPa), andthe like without requiring significant pre-flow tightening of the system900, e.g., over 7 pounds-force (about 58 N).

A sintered frit 954, such as 300 series sintered steel, may be disposedbetween the gasket 908 and the filter 934, on both sides of the filter934, to prevent entry of specified (e.g., too large based on anapplication of the system 900) size particles into passage 956.

According to examples disclosed herein, the driven coupler 910 and thetorque-indicating driving collar 914 may be made of polymers, a metal,or a combination of metals. For example, the driven coupler 910 and thetorque-indicating driving collar 914 may be made of steel such as 17-4steel. Further, the resilient member 944 may be a wave spring, oranother type of resilient member.

Filter 934 may be of any type used in HPLC, including, but not limitedto UHPLC. For example, the filter 934 may be formed of steel, or anothermaterial such as a bio-compatible metal. In this example, media that maybe included in passage 956 may be made of particles, such as, metals,metal oxides, polymers, carbon (e.g., spherical shaped activated carbon,or carbon on silica material), silica-based particles or genericversions thereof, activated charcoal, stationary phase, etc. In otherexamples, the media may include other types of material that areoptimized for the solvent cleanup, and other such uses. The media and/orparticles disclosed herein may be used for any of the filters disclosedherein, and/or other types of columns, online solid phase extraction(SPE), etc.

In some examples, the filter 934 of the relatively short length filtercartridge 906 may be about 30 mm long compared to the filter 1106 of therelatively long length filter cartridge 1102 may be about 50 mm long. Inthis regard, the passage 956 of the relatively short length filtercartridge 906 may include an about 2.1 mm in diameter compared to thepassage 1122 of the relatively long length filter cartridge 1102, whichmay be about 4.6 mm in diameter. Both the filter 934 and the filter 1106may be utilized for HPLC and UHPLC applications.

FIG. 14 is a perspective view of the filter cartridge 906, without thethread details on an external surface 1400 of the filter fitting 912, inaccordance with an example of the present disclosure. FIG. 15 is aperspective view of the filter cartridge 906, with thread details (e.g.,external thread 924) on the external surface of the filter fitting 912,in accordance with an example of the present disclosure.

Referring to FIGS. 9, 14, and 15, the filter cartridge 906 may includethe filter fitting 912 (e.g., a first filter fitting 912) on one side ofa filter 934 (or filter 1106 of FIG. 11), and a second filter fitting936 on a second opposite side of the filter 934 (or filter 1106 of FIG.11). Referring to FIGS. 11, 14, and 15, the filter cartridge 1102 mayinclude a first filter fitting 1108 on one side of a filter 1106 (orfilter 934 of FIG. 9), and a second filter fitting 1110 on a secondopposite side of the filter 1106 (or filter 934 of FIG. 9). As shown inFIGS. 9 and 11, the filter fittings 912 and 936 may include a differentconfiguration compared to the filter fittings 1108 and 1110 torespectively accommodate gaskets 908 and 1104.

As shown in FIG. 9, the filter cartridge 906 may include gasket 908(e.g., a first gasket) disposed in the filter fitting 912 (e.g., a firstfilter fitting), and a gasket 908 (e.g., a second gasket) disposed inthe filter fitting 936 (e.g., a second filter fitting). As shown in FIG.11, the filter cartridge 1102 may include gasket 1104 (e.g., a firstgasket) disposed in the filter fitting 1108 (e.g., a first filterfitting), and a gasket 1104 (e.g., a second gasket) disposed in thefilter fitting 1110 (e.g., a second filter fitting). The gaskets 908 and1104 may include different configurations as shown in FIGS. 9 and 11.

As shown in FIG. 9, the gasket 908 (e.g., a first gasket on the lefthand side and a second gasket on the right hand side in the orientationof FIG. 9) may include a complementary geometry 926 to respectively forma seal against area 938 of the first filter fitting 912 and area 940 ofthe second filter fitting 936.

For the example of FIG. 9, the first filter fitting 912, the secondfilter fitting 936, and the gasket 908 (e.g., a first gasket on the lefthand side and a second gasket on the right hand side in the orientationof FIG. 9) may be radially symmetric about a central axis (which may becoincident with the central axis 920) of the filter cartridge 906.

The gasket 908 (e.g., a first gasket on the left hand side and a secondgasket on the right hand side in the orientation of FIG. 9) may includea central axial channel 942. In an example, the channel 942 may includea diameter of from about 0.01 mm or less to about 0.9 mm, for examplefrom about 0.1 mm to about 0.5 mm, such as a diameter of about 0.3 mm.

The gasket 908 may include a beveled surface 958 adjacent to the filter934 (with frit 954 disposed therebetween). The beveled surface 958 mayinclude an angle relative to a central axis (which may be coincidentwith the central axis 920) of the filter cartridge from about 70 degreesto about 89 degrees.

The gasket 908 may further include a protruding surface 960, which mayinclude an angle relative to a plane that is perpendicular to a centralaxis (which may be coincident with the central axis 920) of the filtercartridge from about 85 degrees to about 89 degrees, such as about 87degrees.

During operation, fluid pressure on the beveled surface 958 mayprimarily generate axially sealing pressure against frit 954 and/orradial sealing pressure against the filter fitting. Thus, the higher thefluid pressure, the higher sealing pressure and more fluid-tight thefilter assembly 904. Accordingly, finger tightening force of from about3 lbf to about 13 lbf, such as about 5 lbf to about 8 lbf on the system900 is sufficient to completely seal the filter assembly 904 without theneed to use external forces to further tighten the system 900.

As shown in FIG. 11, the gasket 1104 (e.g., a first gasket on the lefthand side and a second gasket on the right hand side in the orientationof FIG. 11) may include a complementary geometry to respectively form aseal against a stop shoulder 1116 of the first filter fitting 1108 and astop shoulder 1118 of the second filter fitting 1110. The stop shoulder1116 of the first filter fitting 1108 and the stop shoulder 1118 of thesecond filter fitting 1110 may be perpendicular to a central axis (whichmay be coincident with the central axis 920) of the filter cartridge1102.

For the example of FIG. 11, the first filter fitting 1108, the secondfilter fitting 1110, and the gasket 1104 (e.g., a first gasket on theleft hand side and a second gasket on the right hand side in theorientation of FIG. 11) may be radially symmetric about a central axis(which may be coincident with the central axis 920) of the filtercartridge 1102. The gasket 1104 (e.g., a first gasket on the left handside and a second gasket on the right hand side in the orientation ofFIG. 11) may include a central axial channel 1112. In an example, thechannel 1112 may include a diameter of from about 0.01 mm or less toabout 0.9 mm, for example from about 0.1 mm to about 0.5 mm, such as adiameter of about 0.3 mm

The gasket 1104 may include a beveled surface 1114 adjacent to thefilter 1106. The beveled surface 1114 may include an angle relative to acentral axis (which may be coincident with the central axis 920) of thefilter cartridge from about 70 degrees to about 89 degrees.

The gasket 1104 may further include a protruding surface 1124, which mayinclude an angle relative to a plane that is perpendicular to a centralaxis (which may be coincident with the central axis 920) of the filtercartridge from about 85 degrees to about 89 degrees, such as about 87degrees.

During operation, fluid pressure on the beveled surface 1114 mayprimarily generate axially sealing pressure against frit 1120 and/orradial sealing pressure against the filter fitting. Thus, the higher thefluid pressure, the higher sealing pressure and more fluid-tight thefilter assembly 904. Accordingly, finger tightening force of from about3 lbf to about 13 lbf, such as about 5 lbf to about 8 lbf on the system1100 is sufficient to completely seal the filter assembly 904 withoutthe need to use external forces to further tighten the system 1100.

Referring to FIGS. 9 and 15, the filter fittings 912, 936, 1108, and1110 may include external threads (e.g., the external thread 924). Inthis regard, the driven coupler 910 may include the internal thread 922for threaded engagement with the external thread 924 of the filterfittings 912, 936, 1108, and 1110.

The sintered frit 1120, which may be 300 series sintered steel, may bedisposed between the gasket 1104 and the filter 1106, on both sides ofthe filter 1106, to prevent entry of specified size particles intopassage 1122.

Filter 1106 may be of any type used in HPLC, including, but not limitedto UHPLC. For example, the filter 1106 may be formed of steel, oranother material such as a bio-compatible metal. In this example, mediathat may be included in passage 1122 may be made of particles, such as,metals, metal oxides, polymers, carbon (e.g., spherical shaped activatedcarbon, or carbon on silica material), silica-based particles or genericversions thereof, activated charcoal, stationary phase, etc. In otherexamples, the media may include other types of material that areoptimized for the solvent cleanup, and other such uses. The media and/orparticles disclosed herein may be used for any of the filters disclosedherein, and/or other types of columns, online solid phase extraction(SPE), etc.

FIG. 16 is a perspective view of a driven coupler 910 and atorque-indicating driving collar 914 of the system 900 of FIG. 9, inaccordance with an example of the present disclosure. FIG. 17 is aperspective view illustrating operation of the driven coupler 910 andthe torque-indicating driving collar 914 of FIG. 16, in accordance withan example of the present disclosure.

Referring to FIGS. 9, 16, and 17, the torque-indicating fitting 902 mayinclude the driven coupler 910 including at least one driven tooth 1600,and the torque-indicating driving collar 914 including at least onedriving tooth 1602 positioned to engage with the at least one driventooth 1600 as the torque-indicating driving collar 914 is rotated. Eachdriven tooth 1600 may include a trapezoidal configuration, where anouter face 1604 of the driven tooth 1600 includes a larger surface areacompared to an inner face 1606. In this regard, a line along the edges1608 (which may be sharp or rounded) may terminate at a central pointalong a central longitudinal axis 1610 of the driven coupler 910.Further, the at least one driven tooth 1600 may be located on a proximalend or on a radially outer surface of the driven coupler 910. Examplesof slopes for the driving tooth 1602 (relative to a radial plane) mayinclude less than about 90°, such as about 45°, from about 45° to about15°, from about 30° to about 15°, about 22.5°, and the like.

The torque-indicating driving collar 914 may further include at leastone torque-indicating tooth 1612 positioned adjacent to the at least onedriving tooth 1602 to engage with the at least one driven tooth 1600 asthe torque-indicating driving collar 914 is rotated. Lines along edges(which may be sharp or rounded) of the driving tooth 1602 and thetorque-indicating tooth 1612 may similarly terminate at a central pointalong a central longitudinal axis 1614 of the torque-indicating drivingcollar 914.

The torque-indicating driving collar 914 may further include at leastone axial collar-alignment feature 1616. The at least one axialcollar-alignment feature 1616 may be located radially outer from orinner to the at least one driving tooth 1602.

The properties of the various components of the torque-indicatingfitting 902 may be configured to allow the driving tooth 1602 tofrictionally engage with and drive the driven tooth 1600 until a definedamount of torque is applied (e.g., driven coupler 910 forms a threadedseal with the corresponding filter fittings).

Operation of the system 900 is described with respect to FIGS. 9, 11,and 17.

Referring to FIGS. 9, 11, and 17, at 1700, the thumbpiece 932 (not shownin FIG. 17) may be used to rotate the torque-indicating driving collar914, which may impart rotation on the driven coupler 910 based oncontact of the driving tooth 1602 with the driven tooth 1600.

The torque applied to the driven coupler 910 when a user rotates thethumbpiece 932 may be controlled, for example, to prevent damage tocomponents and facilitate later removal of the torque-indicating fitting902 from a filter cartridge. In an example, the force applied to thedriven coupler 910 may be from about 1 Pounds-force (lbf) or less toabout 32 lbf, for example, the force may be from about 2 lbf to about 24lbf, from about 3 lbf to about 13 lbf, such as about 5 lbf.

At 1702, as the torque exerted on the driven tooth 1600 reaches amaximum specified torque that is equal to a counter-acting force exertedby the resilient member 944 (e.g., as the resilient member 944 iscompressed), as shown at 1704, the torque-indicating driving collar 914may move away from the driven coupler 910 due to the angled contactbetween angled surface 1706 of the driving tooth 1602 with the driventooth 1600.

At 1708, as the torque-indicating driving collar 914 continues to berotated and as the angled surface 1706 of the driving tooth 1602 nolonger contacts the driven tooth 1600, the torque-indicating drivingcollar 914 may freely rotate until contact of the driven tooth 1600 withthe torque-indicating tooth 1612. In this regard, the contact of thedriven tooth 1600 with the torque-indicating tooth 1612 may generate anaudible and physical “click” that may be heard and felt through thethumbpiece 932 to indicate to a user that the torque-indicating fitting902 is properly mounted to the filter cartridge 906 (or 1102) to avoidany unintended leakage associated with the system 900. At this point,once the torque-indicating fittings are properly installed on both sidesof the filter cartridge 906 (or 1102), a user may utilize the system 900as needed.

Examples of Materials

The various components described herein may be fabricated from a varietyof materials including metal and polymers. The materials may beengineered to achieve desired levels of strength, resilience, and thelike.

In some examples, driven couplers 208 and/or 910 and driving collars 220and/or 914 are both fabricated from metals such as steel alloys such asstainless steel. The surfaces of teeth 212, 222, 1600, 1602, and/or 1612may be engineered (e.g., through machining or surface treatments) tohave a defined degree of smoothness or roughness, which will influencethe torque at which the teeth 212, 222, 1600, 1602, and/or 1612 slipand/or maintain contact.

In some examples, gaskets 704 a, 704 b, 908, and/or 1104 may befabricated from a polymer, a plastic, an elastomer, rubber, silicone,nitrile, rubber, polytetrafluoroethylene (PTFE, available under theTEFLON® mark), polychlorotrifluoroethylene, polyether ether ketone(PEEK), metals, and the like.

What has been described and illustrated herein is an example along withsome of its variations. The terms, descriptions and figures used hereinare set forth by way of illustration only and are not meant aslimitations. Many variations are possible within the spirit and scope ofthe subject matter, which is intended to be defined by the followingclaims -and their equivalents- in which all terms are meant in theirbroadest reasonable sense unless otherwise indicated.

1-63. canceled
 64. A system comprising: a female housing includinginternal helical threads; a male housing including external helicalthreads and defining an axial bore adapted and configured to receive afilter or a guard column assembly; and a two-color depth indicatorpositioned external to the male housing or the female housing, thetwo-color depth indicator including: a distal color; and a proximalcolor, wherein the distal color and the proximal color are positionedsuch that, when the female housing or the male housing are tightenedover the counterpart male housing or the female housing: if the filterassembly is correctly inserted and the two-color depth indicator ispositioned external to the male housing, then the female housing coversthe proximal color such that only the distal color is visible and if thefilter assembly is correctly inserted and the two-color depth indicatoris positioned external to female housing, then a cover hides theproximal color such that only the distal color is visible; if the filterassembly is incorrectly inserted or is defective, both the proximalcolor and the distal color are visible; and if no filter assembly isinserted, the female housing or the cover hides both the proximal colorand the distal color such that neither the proximal color nor the distalcolor are visible.
 65. The system of claim 64, wherein the two-colordepth indicator is formed through at least one process includingprinting, painting, electroplating, brush electroplating, or anodizing.66. The system of claim 64, wherein the two-color depth indicator is aring placed over the external helical threads of the male housing. 67.The system of claim 66, wherein the ring is threaded over the externalhelical threads of the male housing.
 68. The system of claim 64, whereinthe two-color depth indicator includes an adhesive tape, a sticker, anda rubber band.
 69. The system of claim 64, wherein the female housingfurther includes a distal, unthreaded portion adjacent to the internalhelical threads, the distal, unthreaded portion including an axiallength equal to or exceeding an axial length of the two-color depthindicator.
 70. The system of claim 64, wherein: the distal color isgreen; and the proximal color is red.
 71. A filter cartridge comprising:a first filter fitting on one side of a filter; a second filter fittingon a second opposite side of the filter; a first gasket disposed in thefirst filter fitting; and a second gasket disposed in the second filterfitting.
 72. The filter cartridge of claim 71, wherein the first filterfitting and the second filter fitting include external threads.
 73. Thefilter cartridge of claim 71, wherein the first gasket and second gasketinclude a complementary geometry to respectively form a seal against astop shoulder of the first filter fitting and a stop shoulder of thesecond filter fitting.
 74. The filter cartridge of claim 73, wherein thestop shoulder of the first filter fitting and the stop shoulder of thesecond filter fitting are perpendicular to a central axis of the filtercartridge.
 75. The filter cartridge of claim 71, wherein the firstfilter fitting, the second filter fitting, the first gasket, and thesecond gasket are radially symmetric about a central axis of the filtercartridge.
 76. The filter cartridge of claim 71, wherein the firstgasket and the second gasket each include a central axial bore.
 77. Thefilter cartridge of claim 71, wherein the first gasket and the secondgasket include a beveled surface adjacent to the filter.
 78. The filtercartridge of claim 77, wherein the beveled surface has an angle relativeto a central axis of the filter cartridge from about 70 degrees to about89 degrees.